Liquid oxygen &#34;walkaround&#34; unit



Jan. 27, 1948. s. s. PRENTISS LIQUID OXYGEN WALKAROUND UNIT Filed Nov. 5, 1945 INVENTOR SPENCER S. PRENTISS AND M Ma ATTORNEYS- Patented Jan. 27, 1948 2,434,956

LIQUID OXYGEN WALKAROUND UNIT Spencer S. Prentiss, Washington, D. 0., assignor to The United States of America, as represented by the Secretary of War Application November 5,1945, Serial No. 626.870 (Cl. 62-1) (Granted under the act of March 3, 1883, as

9 Claims.

amended April 30, 1928; 370 0. G. 757) v The invention described herein may be manufactured and used by or for the Government for governmental purposes without payment to me of any royalty thereon.

This invention relates to a portable oxygen the line being filled with oxygen in the gaseous state. A tube It enters the top of the closure l4, being pressure-sealed where it enters, thence loosely downward through the neck extension 9 and the neck I! leaving a space I! between them,

5 walkaround unit having reference to a unit of then downward substantial y to e ottom-of such weight and capacity as may be carried the vessel. Conduit means l8 and 20 connect the about on the person to supply the user with closure l4 and the tube l6 respectively to the breathing oxygen for a period of several hours. upp and lower p ays 22 and 24 of a An object of this invention is to provide a'unit 1U gravity-operated valve 26. of this class having storage space for liquid oxy- The gravity-operated valve 25 has a weighted gen and having means to convert the liquid oxyvalve member 28 which normally rests on and gen into breathing oxygen as fast as is required. oses t lower passageway 24 but will close the Another object of the invention is to provide p way 22 and open the p ssa y 24 when an oxygen unit in which the takeoff will always the device is inverted as shown in Fig. 2 in which be connected to that part of the container in the line 25 represents the level of the liquid oxywhich the oxygen is in the gas phase no matter n 5 n h Vessel l and the space 2 that whether the container is upright or inverted. part of the contents which is in the gaseous Another object of the invention is to provide state. The takeoff 30 from the valve 26 proceeds means whereby the normal rate of conversion to the inner turn of a warming coil 32 which from the liquid to the gas phase may be augspirals around the neck t2, the turns lying mented at the will of the user. against the jacket of the vessel [0 to which Another object of the invention is to provide jacket they may be soldered or similarly secured means whereby the normal rate of conversion for mechanical support as well as for thermal from the liquid to a gas phase may be augmented conductivity. I automatically to maintain a given preselected The outer turn of the warming coil 3? progas pressure. ceeds by way of a conduit 34 to the input side Other objects and advantages will be recog- 36 of a demand regulator. This regulator connized as the invention is further described with sists of any of the several commercially available reference to the drawings wherein: designs which are well known in the art but may Fig. 1 is a schematic view showing a device preferably be of the diluter type for economy of embodying my invention in its normal operating operation. The output side 40 of the demand condition. regulator is connected to an oxygen mask not Fig. 2 is a schematic viewshowing the device shown. in position to increase the normal rate of con- As an alternative, the demand regulator may version from the liquid phase to the gas phase. be replaced by a valve and a constant-flow regu- Fig.3 shows a modification of the device in the lator by using a suitable economizer such as a normal operating condition, this modification berubber breather bag or similar device. A filler ing provided with automatic means for convalve 42 is provided at the outer end of the tube trolling conversion from the liquid to the gas I6 and event valve 44 communicates with the phase. closure l4. A safety valve 46 and a pressure Fig. 4 shows the action of the device of Fig. 3 gauge 48 are connected to the conduit 34. when breathing oxygen is being drawn ofi faster The operation of the device shown in Figs. 1 than the normal conversion rate. and 2 is substantially as follows:

Fig. 5 shows the action of the device of Fig. 3 The filler valve 42 is connected to a source of when it has for any reason been inverted. liquid oxygen under several p. s. i. pressure and Like reference characters refer to like parts opened, the vent valve 44 being simultaneously throughout the several views. opened and left open until liquid oxygen flows A vacuum-jacketed vessel in which may be of therefrom showing that the device is completely the Dewar type of appropriate size, preferably 50 filled with the liquid. Both of the valves 42 n alf to n litre p y. h n tension and 44 are then closed and disconnection of the 9 of the neck l2 of the vessel provided with a valve 42 from the supply source is effected and closure l4. The line H indicates the level of the the apparatus placed in a upright position until liquid oxygen l 5 in the vessel In when the device it is to be used. is upright as seen in Fig. l, the space l3 above When thus filled and stored, the pressure will buildup at a rate of not more than several p. s. 1. per hour, so that no oxygen will be wasted for several hours,-that is, not until the pressure builds up to the value aTwhich thesafety valve 46 is set, which value may prefrably be about 125 p. s. i. In use the device may-be attached to the user by means of a standard clothes clip',"*

a small spring scale being interposed between the clip and the device to indicate the state of the charge. When the wearer's mask is attached to the demand regulator, oxygen taken from the demand regulator may be replenished by flow from the space 13, through the space H between the inside of the neck. I 2 and the tube It, through the extension 9 into the closure l4, thence through theconduit l3, gravity valve 26, conduit 30, warming coil 32 and conduit '34 into the demand regulator. This path may hereinafter be referred to as the primaryfiuid channel.

Gas phase oxygen will usually be used faster than the normal conversion rate, thereby lowering the pressure and consequently lowering the boiling point. When the pressure approaches a value for satisfactory operation of the demand regulator, as may be evidenced by the gauge 43 or by the resistance to breathing, the apparatus may be inverted for a short period of time as in Fig. 2. It is noted that the higher the pressure at which the safety valve 46 is set, the less frequently the device must be inverted for a given oxygen consumption.

When the device is inverted as in Fig- 2, the member 28 of the gravity valve 28 drops, thereby opening the passageway 24 and closing the passageway 22. Moreover, the gas space, which in Fig. 1 wasat 13 above the line ll, will, in Fig. 2, beat 21 above the line 25. Furthermore, in the normal position Fig. 1, the space H, extension 9, closure l4 and conduit II were filled with gas phase oxygen, and the pipe ii and conduit 20 contained liquid, while in the inverted position of Fig. 2, the space 11, extension 4, closure l4, and conduit 13 contained liquid and the pipe I3 and conduit 23 contained gas.

It follows that, when the device is inverted as shown in Fig. 2, the extension 3, closure l4 and conduit l8, being without heat insulation, warm the liquid, thereby raising, its boiling point and increasing the pressu'e for more rapid conversion, the converted gas phase oxygen passing down through the tube 14 and through the conduit 20,

passageway 24, gravityvalve 23, conduit 30, warming coil 32, conduit 34 to the demand regulator.

This path. may hereinafter be referred to as thesecondary fluid channel. When the gauge 48 indicates that the pressure has again reached the desired value, the device may be returned to' the upright position.

In the modification shown in Flgs..3 to 5, the

' same "Dewar container Ill, pressure gauge 43,

safety valve 48, closure l4 and demand regulator 38 may be used in the same way hereinbefore described. The gravity valve 23 of the modified device, however, is operative only when the apparatus is inverted as shown in Fig. 5 where the valve member H has closed the passageway 23.

The device, Figs. 3 through 5 is further modified by the addition of a pressure controlled sylphon"-operated bypass valve 43 which comprises a casing 35 in which a sylphon 31 has the upper end-secured to the top of the casing, the inside of the sylphon" having been filled with air or other suitable gas at a predetermined pressure and sealed, and the lower end being provided with a valve member 33 which is' forced by expansion of the -sylphon" to close the passageway H which prevents fluid flow through the passageway 43 into the conduit 2!. By providing the inside of the sylphon" with a preselected initial pressure when the valve 39 is in closed position, the pressure at which the gas phase oxygen around the sylphon will keep the valve 33 011 its seat 41,. may be selectively controlled. For purposes of illustration let it be assumed that it is required to maintainthe gas phase oxygen around the outside of the sylphon at a pressure of approximately lfi'pss. i. to keep the valve 39 open, 16 p. s. i. being about as low as will safely operate the demand regulator. A conduit 33 connects the gravity-operated valve 23 to the sylphon"-operated valve 45. The conduit 2| connects the tube I6 to the inside turn of the warming coil 32. The conduit l3 connects the closure [4 to the passageway 23 into the gravity valve 23.

The operation of the modified apparatus shown in Figs. 3 through 5 is substantially as follows:

The device should first be filled with liquid oxygen at several p. s. i. pressure as described with reference to Fig. 1. It is noted that when the vessel is being filled, the valve part 33 will be on the seat 4|. When conversion has thereafter proceeded until the valve part 33 rises from the seat 4|, oxygen under at least 16 p. s. i. will pass through the primary fluid channel which includes the space H, container 14, conduit l3, gravity valve 23, conduit 33 sylphon-operated valve 45, cell 32 and conduit 34, to the demand regulator.

If no oxygen is immediately used, the pressure may build-up to a point where the safety valve 46 opens, which may be assumed for illustrative purposes, to be at about 45 p. s. i. This low safety valve setting is practicable in this exempliflcation of the invention where recharging is automatic, whereas, in the first exemplification described, a higher safety valve setting is desirable to lessen the number of times that the user must give his attention to inverting the device for recharging. On the other hand, if oxygen is used faster than the normal conversion rate, the pressure in the casing 35 around the sylphon 31 will fall until the sylphon" valve 45 closes as seen in Fig. 4, whereupon liquid oxygen I! will be taken from the bottom of the container l3 and passed through the secondary fluid channel which includes the tube I6, conduit 2!, coil 32 and conduit 34, to the demand regulator 34. Since the conduits 2| and 34 and coil 32 are exposed to the atmosphere, pressure will build up rapidly within the container ill, neck l2, closure 14 and sylphon-valve 45 and again open the valve for normal operation as in Fig. 3.

From the foregoing it will be seen that, because of movement of oxygen through a secondary channel when more is used than, is normally converted, the entire charge may be expended without attention by the user.

Should the device for any reason become inverted and the gravity valve 23 thereby closed as seen in Fig. 5, liquid oxygen will extend into a part of the primary channel which includes the neck extension 3, closure 14, and conduit It. to be warmed for conversion, and gas phase oxygen will flow from the space 21 above the line 25 through the secondary channel which includes the tube I6, conduit 21, coil 32 and conduit 34 to the demand regulator. Discharge by way of the safety valve 46 will occur if the apparatus is left in the inverted condition, Fig. 5, for too long a period.'

Having shown and described several forms of my invention, I claim:

1. In a device for storing liquid oxygen to be carried on the person and for converting it into breathing oxygen and delivering it to a demand regulator as fast as needed, a heat insulated container adapted to hold the liquid oxygen, said container having an opening in the top, a hollow closure for said opening whereby the inside of said container is connected to the hollow of said closure, a vent valve connected to the hollow of said closure, a tube extending pressure tight through the top of said closure to a point near the bottom of said container, a warming coil having its turns lying onand secured to the outer surface of said container and around ing coil, a second conduit connectingthe other end of said warming coil to said demand regulator, a valve adapted to be open when the device is upright and closed when the device is inverted,a second valve operative to be open when the pressure within the device is above a predetermined value and closed when said pressure is below said predetermined value, and passageways connecting the hollow of the closure to the inlet side of the first said valve, the outlet of the first said valve to the inlet of said second valve, and the outlet of said second valve to the first said conduit.

,14. In a device for storing liquid oxygen and for controlling its conversion into gaseous oxygen and said opening, a conduit connecting said tube at a point above said closure to the inner turn of said warming coil, 3, second conduit connecting the outer turn of said warming coil to said demand regulator, a safety valve and a pressure gauge connected to said second conduit, a gravity valve operative to be open when the device is upright and closed when the device is inverted, a pressure operated valve operative to be open when the pressure Within the device is above a predetermined value and closed when said pressure is below said predetermined value, and passageways connecting the hollow of the closure to the inlet side of said gravity valve, the outlet of said gravity valve to the inlet of said pressure operated valve, and the outlet of said pressure operated valve to the first said conduit.

2. In a device for storing liquid oxygen to be carried on the person and for converting it into breathing oxygen and delivering it to a demand regulator as fast as needed, a heat insulated container adapted to hold the liquid oxygen, said necting said tube at a point above said closure to one end of said warming coil, a second conduit connecting the other end of said warming coil to said demand regulator, a gravity valve operative to be open when the device is upright and closed when the device is inverted, a pressure operated valve operative to be open'when the pressure within the device is above a predetermined value and closed when sad pressure is below said predetermined value, nd passageways connecting the'hollow of the closure to the inlet side of said gravity valve, the outlet of said gravity valve to the inlet of ,said pressure operated valve, and the outlet of said pressure operated valve to the first said conduit.

its delivery to'a demand regulator,.a heat insulated container adapted to hold the liquid oxygen, a tube extending into said container to a point near the bottom, said container being sealed against leakage around said tube, a warming coil,

a fluid conducting means connecting said tube at a point outside said container to said warming coil, a second'condult connecting said warming coil to said demand regulator, a valve operative to be open when the device is upright and closed when the device is inverted, a second valve operative to be open when the pressure within the device is'above a predetermined value and closed when said pressure is below said predetermined value, and passageways connecting the top of the container to the inlet side of the first said valve,

3. In a device for storing liquid oxygen and for converting it into gaseous oxygen and controlling its delivery to a demand regulator, a heat insulated container adapted to hold the liquid oxy:

gen, said container having an opening in the top, a hollow closure for said opening whereby the inside of said container is connected to the holthe outlet of the first said valve to the inlet of said second valve, and the outlet of said second valve to the first said conduit.

5. In a device for storing liquid oxygen and controlling its conversion into gas phase oxygen,

-a heat insulated container, a warming coil outside said container, a primary fluid channel from the inside of said container at the top thereof to said warming coil, a econdary fluid'channel from the inside of said container at the bottom thereof to said warming coil, and two means insaid primary channel, one operative to automatically close said primary channel whenever the device is inverted, and the other operative automatically to close said primary channel whenever the pressure in said primary channel falls below a predetermined value.

6. In a device for storing liquid oxygen and L controllingits conversion into gas phase oxygen,

the primary fluid channel and open the secondary v fluid channel whenever said device is inverted.

'7. In a device for storing liquid oxygen and controlling its conversioninto gas phase oxygen, a heat insulated container, a warming coil outside said container, a primary fluid channel from the inside of said container at the top thereof to said warming coil, a secondary fluid channel from the inside of said container at the bottom thereof to said warming coil, and a gravity actuable valve, operative when the device is upright, to open said primary fluid channel and close said secondary fluid channel, and operative when the device is inverted, to close said primary fluid channel and open said secondary fluid channel.

8. In a device for storing liquid oxygen and controlling it conversion into gas phase oxygen, 76

a heat insulated container, a warming coil out- 7 side said container, a primary fluid channel from the inside oi said container at the top thereof to said warming coil, a secondary fluid channel from the inside of said container at the bottom thereof to said warming coil, and gravity actuated means associated with said primary fluid channel automatically operating when the device is inverted to close said primary fluid channel, whereby fluid may flow only through the secondary fluid channel.

said primary channel automatically operative when the device is inverted to close said primary fluid channel, whereby fluid may flow only through said secondary fluid channel.

SPENCER S. PRENTISS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,505,095 Heylandt Aug. 19, 1924 FOREIGN PATENTS Number Country Date 622,756 Germany Dec. 5, 1935 

